E-Link Gateway Installation Instructions
12
Electrical Noise Mitigation to Equipment
The likelihood of transient voltage is greatly reduced if
the E-Link Gateway is close-coupled to the Micro
Panel. Close-coupling requires that the E-Link
Gateway and Micro Panel share the same line voltage
power source and are physically close to one another.
Typically, the E-link Gateway is mounted on the Micro
Panel enclosure. This scenario ensures a short
communication cable, which is usually protected
entirely within the two enclosures.
Electrical Noise Mitigation
for E-Link to BAS
When the E-Link is used in an electrically hostile
environment (for example, with VSD-enabled
equipment), a double-shielded cable should be used to
help mitigate the adverse effects electrical noise can
have on the system. The double-shielded cable should
connect the E-Link’s BAS port (Port 1 or Port 4) to the
next controller(s) in the daisy-chained network.
The outer shield of the double-shielded cable should
be grounded directly at the
low noise end
(the end
most distant from the VSD), and ideally, indirectly
through an appropriate capacitor at the
high noise end
(the end closest to the VSD). If a capacitor is not
available, the outer shield may be left unconnected, or
tied directly to ground. The best results on the site
determine the specific termination strategy employed.
The inner shield of the double-shielded cable should be
grounded directly at the
low noise end
(the end most
distant from the VSD), and left open at the
high noise
end
(the end closest to the VSD).
Types of Communication Ports
The E-Link Gateway uses three communication
protocols to connect to other devices: RS-485 and FFT
are used for multi-drop networking, whereas RS-232 is
primarily used for point-to-point connectivity.
RS-485
The RS-485 standard uses three conductors to
connect network nodes: two signal wires and a
reference. The E-Link Gateway uses either a third wire
for the reference or the building’s infrastructure. The
wiring method depends on the port being used: an
electrically isolated Port 1 typically uses a third wire,
whereas Ports 2 and 3 normally use chassis or building
ground for the reference.
Setup and Adjustments
There are a number of settings that you may make on
an E-Link Gateway or to the connected equipment.
Network Termination
Terminate all End-of-Line (EOL) devices at either end
of the RS-485 bus (that connect to only one set of
RS-485 network wires). EOL termination provides
biasing of the network, and assists in returning the
signal to a normal state in the event of voltage
transients. If the E-link Gateway happens to be the
end-of-line device, terminate the network by setting the
EOL switch located above each of the
E-Link Gateway’s RS-485 ports to the ON position.
Media Access Control (MAC) Address
The E-Link Gateway’s network hardware address is set
on a single 8-way DIP switch. Switch 8, the T switch, is
reserved to invoke Terminal mode on Port 3, leaving
the remaining 7 switches for setting the address. Refer
to the
E-Link Gateway Commissioning and
Troubleshooting Technical Bulletin
(LIT-12011238)
for more details.
The network address is binary weighted, allowing you
to set up to 127 unique addresses.
APP Group A
APP Group A uses a 6-way DIP switch to select the
desired equipment’s profile. This switch is also binary
weighted, allowing up to 63 unique selections.
IMPORTANT:
Do not run communication cables in
close proximity to, or parallel with, high-voltage
power cables (maintain at least 457.2 mm [18 in.] of
separation, or use a grounded metal conduit).
IMPORTANT:
Ensure that the EOL switches are
not set to the ON position for controllers that do not
terminate the RS-485 network.
Figure 8: RS-485 EOL Switches
Figure 9: MAC Dip Switch
